The present invention relates to a process for the polymerization of cycloolefins of 8 or 12 carbon atoms having one or more isolated, i.e., non-conjugated, double bonds in the ring, optionally in the presence of a solvent, with the aid of a catalyst consisting of tungsten hexachloride and a cocatalyst.
The production of polyalkenamers from cycloolefins with the aid of metathesis catalysts is conventional, e.g. see G. Dall'Asta in "Makromol. Chem." (Macromolecular Chemistry) 154 : 1-19 (1972). Metathesis catalysts are homogeneous and heterogeneous catalysts containing compounds of metals of subgroups V-VII of the periodic table, primarily those of niobium, tantalum, molybdenum, tungsten and rhenium, as well as optionally compounds of the metals of main groups I-III of the periodic table, e.g., the alkyls or hydrides thereof, if desired with additional ligands, e.g., halogen, alkoxy or carboxylate or, in place thereof, Lewis acids. The metathesis catalysts can also include, as is known, further activating additives, such as alcohols, epoxides, tert.-butyl hypochlorite, peroxides, carboxylic acids, aromatic nitro compounds, vinyl halides, vinyl and allyl ethers and esters, etc.; see for example, DAS (German Published Application) No. 1,072,811; French Pat. Nos. 1,394,380 and 1,467,720; Dutch Pat. Applications Nos. 65-10331, 66-05105, 66-14413, 67-04424, 67-14559, 68-06208, 68-06211 and 68-06209.
Since the customary alkyl or hydride compounds of main groups I-III of the periodic table are both expensive and generally difficult to handle, attempts have been made to conduct metathesis reactions without adding such compounds.
For example, it is known from Italian Pat. 784,307 that a small amount of polymer is obtained after long reaction times by treating cyclopentene with tungsten hexachloride.
Furthermore, a process for the polymerization of various cycloolefins is known from DOS (German Unexamined Laid-Open Application) No. 1,909,226 wherein, inter alia, tungsten hexachloride and an aluminum trihalide are utilized as the catalyst system.
It is furthermore known that 1,5-cyclooctadiene can be converted into polymers with a combination of tungsten hexachloride and phenyl diazomethane, as reported in "Eur. Polym. J.", 10 : 901 (1974).
Finally, it is known from DOS No. 2,332,564 to polymerize 1,5-cyclooctadiene with halides of tungsten, molybdenum, tantalum or rhenium as the catalyst in the presence of certain bicyclo-[2,2,1]-1,5-heptadienes.
All of these processes of the prior art have at least one of the following disadvantages:
1. A low activity of the catalyst system employed and consequently a high amount of catalyst required, leading to high ash contents in the polymers.
2. Poor solubility of the catalyst components and ensuing difficulties in dosing of the catalyst.
3. Low selectivity of polyalkenamer formation by the favoring of undesired secondary reactions.
4. Use of expensive or difficult-to-produce compounds as the cocatalysts.
It is, therefore, an object of this invention to mitigate or overcome the above disadvantages of the processes of the relevant prior art.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.